A turbine drilling motor produces rotary motion in response to flow of drilling fluid through the motor. In general, turbine drilling motors are used when relatively high rotational speed at relatively low torque is desired, when drilling complex wellbore trajectories, etc.
Unfortunately, if a drill bit rotated by a typical turbine drilling motor becomes stuck, the drill bit cannot be rotated by rotating a section of a drill string above the drilling motor. This can make it very difficult to free a stuck drill bit.
Therefore, it will be appreciated that improvements are continually needed in the arts of constructing and operating drilling motors. Such improvements may be used with drilling motors other than turbine-type drilling motors.